Information for small house enthusiasts.

Roof Framing Basics

Framing the Roof of Your Small Housevs. Using Trusses

It is my opinion that the quickest way to get a roof on anything 500 square feet or more is to construct trusses.

The more faces you have to a roof the more complicated the framing becomes and consequently you will face a significant increase in the cost of construction. As you increase the faces and angles of a roof line the main thing that increases is the time it takes to frame in intricate and complicated geometry. Therefore a shed style roof that only contains one side is the most cost effective.

Additionally there is other fairly cost effective roof styles such as the gable roof which is a two sided triangular roof, a gambrel roof which is more bell shaped when viewed from the side, a hip roof which is in the shape of a pyramid, or a peaked hip roof which is two-sided and similar to the gable roof.

It is important to remember to provide a sufficient overhang or “soffit” for drainage and runoff as well as wall protection. This is step is especially significant if you have built “alternative” walls such as straw bale, cordwood, or cob, and may mean framing in the roof to stretch the protecting overhang above the walls.

My advice to Do-It-Yourselfers is to subcontract out any roof framing, even for a simple project. The integrity of the roof is critical is keeping out water and increasing the life of the house. Find a subcontractor that is knowledgeable in this area or better yet, specializes in roof framing. Shoddy workmanship on the roof, especially the shingling or other sheathing, will come back to haunt you.

The advantage to framing a roof for a small house is that it most likely will be of a simpler design. I look at some McMansions and am just boggled by the complexity of the roof lines. Most small houses have a simple gable roof, or an integration of 2 gable roofs perpendicular to each other.

The one exception I’ve seen is houses by Ross Chapin. Even the small cottages have some pretty interesting and intricate designs. In the end it gives the house a unique charm and personality and an experienced framer should be able to handle that kind of design. However, this is probably something a Do-It-Yourselfer should avoid, especially if this is your first small house.

Although framing a roof is not a job for a novice carpenter, a simple roof is attainable by the Do It Yourselfer with some basic tools. A saw, framing square and tape measure will accomplish the job of installing the trusses and the hip and valley rafters. The dimension knowledge you need is the pitch of the roof and its relationship to the span of the roof which employs simple geometry. This same equation applies to building the trusses.

Although there is the basic equation, there are many other factors to consider depending upon the type of roof you choose. As the Do It Yourselfer, if you feel about building or framing a roof to the proper specification, it is best to leave it to a qualified subcontractor to ensure everything is done correctly. Taking all the proper steps now instead of cutting corners will pay off in the long term.

Here are some pictures from the roof framing, dormer framing, and porch framing portions of our house building project:

Here the central peak roof rafter is in place; it consists of several 2×12’s sandwiched together on-site. I can’t believe the framer wanted to go out on the ridge like that– makes my stomach turn just to think about it. I’ll gladly pay somebody else to do that.

Next time I would definitely go with pre-assembled trusses. This is one thing I didn’t really think about… you have to order trusses several weeks ahead of time. The plans called for the more traditional stick-framed roof, but it could’ve easily been adapted to trusses.

Additionally, trusses can be made from smaller pieces of lumber (smaller trees) or even composite materials. This avoids having to use larger pieces of lumber from older trees (generally not a good forestry practice). And because a truss is, essentially, one integrated load-bearing unit held together with some pretty serious fasteners, it makes the job of the framers a lot easier. So the extra cost of trusses is compensated for by less time (ie. money) is takes for your building crew to get the roof up.

A closer view, and different angle, of the rafters going up. The guy sitting up of the ridge had a rope that he’d let down for someone on the floor to wrap around the end of the next rafter to come up. He’d then just muscle it up and affix it to the next joist hanger.

This is the east side of the house showing the shed dormer.

Here you can see the framing on the 2 front gable dormers. 2 small gable dormers over a large porch is a classic “cabin” style. The dormers really aren’t that hard to frame and finish, and they add a lot of architectural interest to an otherwise boring facade.

This view is looking south across the porch. The porch is really a shed dormer of sorts. The rafters tie directly into the roof rafters.